/**
 * created by lpw
 */
public class TestClass {
    public static void main(String[] args) {
        int n = 12;
        int result = recursion(n);
        System.out.println(result);
    }

    /**
     * 使用递归计算兔子数量
     */
    private static int recursion(int n) {
        if (n == 1 || n == 2) {
            return 1;
        } else {
            return recursion(n - 1) + recursion(n - 2);
        }
    }
}